Many web sites on the Internet World Wide Web regularly display advertisements. The particular advertisement that is displayed when a viewer accesses a web site can either be stored locally on the web site or it can be stored on a central server. (As used herein the term viewer refers to an individual who views or looks at a web page using a program such as a web browser).
The Hyper Text Transfer Protocol (HTTP) and the Hyper Text Mark Up Language (HTML) provide a mechanism whereby a web page can easily reference material located on a remote server. The HTTP mechanisms for referencing and obtaining material from a remote server is useful in providing advertising material for display to viewers. There are commercially available systems which provide advertising material for web sites from a central server and various web pages have HTML references to this central server. With such an arrangement, when a viewer accesses a web page which has an appropriate HTML reference, the viewer sees advertisement that is provided by the central server.
Using standard HTTP facilities it is possible to track when a particular viewer accesses a web site and thus it is possible to compile a data base which in essence provides a profile of the sites a particular viewer has accessed. Furthermore, it is known that particular categories of viewers generally access particular types of web sites. The capabilities inherent in the World Wide Web for tracking the sites that a viewer has seen provides a mechanism for targeting particular advertisements to particular categories of viewers.
There are prior art systems which provide advertisements from a central server that has a data base of information concerning characteristics of viewers. A data base of viewer information can be compiled from a variety of sources including the information about a viewer which is available when a viewer accesses a server. In such prior art systems, the particular advertisement which is displayed when a particular viewer accesses a web site is determined by the characteristics of the viewer as provided by the data base of viewer information and by other information such as the characteristics of the web site which the viewer has accessed. Using such systems advertisers can target advertisements by criteria such as web site category, geographic location of the viewer, the operating system of the viewer's computer, the type of browser which the viewer is using, the Internet domain type of the viewer, etc.
Advertisers who use such prior art systems must specify in advance, the targeting criteria they want to use for their advertisements. The central server then provides advertisements to viewers based upon (a) the targeting criteria provided by the advertisers (b) the information which the central server has in its data base concerning the particular viewer, (c) information about the web site that has been accessed by the viewer and (d) other information available to the central server such as the time of day.